Hydraulic ram pump

ABSTRACT

The invention relates to a hydraulic ram pump, comprising: a propulsion water line fed with propulsion water, a delivery line which can be connected to delivery water via a bottom valve, a ram pump valve which is connected to the propulsion water line and delivery line, the propulsion water flowing into the delivery line when the ram pump valve is open and, after the closing of the ram pump valve, the water column flowing further in the delivery line sucking in delivery water via the bottom valve, the ram pump valve being held by spring force in its closed position separating the propulsion water line from the delivery line, and a pressure reservoir being provided, which is connected to the propulsion water line upstream of the ram pump valve in the direction of flow, the valve member being of annular design, axially movable and tightly connected to the delivery line, the effective cross section of this connection being larger than the cross section of the valve seat, and the valve seat of the ram pump valve and the valve seat of the bottom valve being mechanically coupled in order to transmit kinetic energy.

BACKGROUND OF THE INVENTION

The invention relates to a hydraulic ram pump for converting low amountsof water at high pressure into large amounts of water at low pressure.Such ram pumps are also designated suction rams. Rams denote ram pumpswhich can be used in reverse for the conversion of large amounts ofwater at low pressure into low amounts of water at high pressure. Theram pump according to the invention can do both, that is to say it canoptionally be used to increase pressure or to increase volume flow.

Suction rams have been known at least since 1905 (“Trägheitsmaschinenals Möglichkeit der hydraulisch-mechanischen Energieumformung” [Inertialmachines as an option for hydraulic-mechanical energy conversion],presentation by Ivan Cyphelly, Fegawerk/Switzerland, held at the IHP ofRWTH Aachen, Prof. Backé, Jun 21, 1991). They employ a ram valve which,as in the case of the hydraulic rams having a propulsion water pipe anda natural drop, is abruptly closed by the hydrodynamic pressure dropwhich is produced by the water flowing through the valve.

In the case of known suction rams (for example German Patent No.804,288, 1949, or in the case of the suction ram still built today bythe company Fegawerk S. A., Le Locie/Switzerland), when the ram valvecloses the kinetic energy of the flowing water in the propulsion waterline is dissipated, because the propulsion water is stopped. In order tokeep this loss as small as possible, the suction ram from Fegawerk hasas the propulsion water line a hose having an extremely large crosssection, by which means high velocities of the propulsion water areadditionally avoided.

The above-mentioned known suction rams require a specific constantpropulsion water volume flow for satisfactory functioning, since whenthe propulsion water volume flow falls below that needed, the ram pumpvalve no longer closes and the efficiency falls to zero.

The ram valve is exposed to a particularly high loading as a result ofthe abrupt stopping of the propulsion water column, this loading beingstill considerably higher in known suction rams than in conventionalhydraulic rams in which, as the result of the stopping of the propulsionwater column, the pressure which is backed up at the valve is only thatwhich must be achieved in order to deliver into an air receiver. Thishigh loading on the ram pump valve has an unfavorable effect on thelifetime of the known suction ram.

These disadvantages are overcome by the ram pump described in the GermanPatent Application DE 19520343, which is not a prior publication (EPCArt. 54(3)), according to which the ram pump valve is not formed as anonreturn valve, as in the previously mentioned prior art, which is heldopen by spring force and closed by the propulsion water flow, but as avalve which is held closed by spring force and opened by the propulsionwater pressure.

SUMMARY OF THE INVENTION

Furthermore, according to the invention, provision is made to actuatethe ram pump valve cyclically in the manner of an oscillatory circuit incooperation with a pressure reservoir element which is likewise acted onby the propulsion water. Because of its construction, this suction ramcan operate both to increase pressure and also to increase volume flow.

Since in the case of this ram pump the propulsion water pressure istaken up, before the opening of the ram pump valve, by thepressure-adjustable element of a pressure reservoir element, it isensured that the propulsion water is not stopped abruptly when the rampump is operating but rather can be fed to the latter continuously, bywhich means the ram pump valve is distinctly relieved of load incomparison with the prior art, which is to the benefit of the lifetimeof the ram pump as a whole.

By means of the construction of the ram pump valve of this ram pump as aclosing valve, and its driving by the propulsion water in conjunctionwith a pressure reservoir element, it is furthermore achieved that theram pump valve still opens even at the smallest propulsion water volumeflow, since the opening pressure for the ram pump valve is built up bythe pressure reservoir element even given a minimal propulsion waterflow. This therefore also achieves a distinct increase in the efficiencyof the ram pump in comparison to the suction ram treated above.

Further details of this ram pump are explained in more detail belowusing FIGS. 1 and 2 of the drawing, according to which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a first embodiment, and

FIG. 2 shows a second embodiment of the ram pump described in DE19520343, which is not a prior publication.

FIG. 3 shows a longitudinal sectional view through a preferredembodiment of the ram pump.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The hydraulic ram pump shown in FIGS. 1 and 2 in general comprises in aconventional way a propulsion water line 1, a delivery water line 2, aram pump valve 3 and a bottom valve 4 for sucking up delivery water.Located at the end of the delivery water line 2 is the ram outlet 9. Theram pump valve 3 comprises a piston 3 a and a restoring or closingspring 3 b which biases the piston 3 a against a valve seat 6. The rampump valve 3 is held closed by a spring.

Furthermore, provision is made that the propulsion water line 1 isconnected not only as in the prior art to the pressure side of the rampump valve 3 but additionally to a spring reservoir 5.

The pressure reservoir element 5 is formed as a spring reservoir in theembodiments of the ram pump shown in FIGS. 1 and 2.

According to the embodiment shown in FIG. 1, the spring reservoir 5 hasits own casing 5 c, which communicates with the propulsion water line 1upstream of the ram pump valve 3. Located in the casing 5 c is a piston5 a which is biased by a spring 5 b and which forms thepressure-adjustable element of the pressure reservoir element.

The piston 3 a, the restoring spring 3 b and the valve seat of the rampump valve 3 are likewise accommodated in their own casing 3 c, separatefrom the casing 5 c, in the case of the embodiment of the ram pump shownin FIG. 1, with the result that the ram pump valve 3 and the springreservoir 5 are effectively connected to each other only via thepropulsion water.

In FIG. 2, the elements of the spring reservoir 5 and of the ram pumpvalve 3 are accommodated in a common casing 10 and coupled mechanicallyto one another: the piston 5 a of the spring reservoir 5 is arranged atthe upper end of the coupled piston-spring system, and the pressurereservoir spring 5 b connects the piston 5 a to the piston 3 a, locatedbeneath the latter, of the ram pump valve 3, whose restoring spring 3 bruns in the upward direction and is fixed at a stationary abutment 11 inthe casing 10. The lower end of the casing dips into the delivery waterand is closed by the bottom valve 4.

The propulsion water line opens into the casing 10 at the level of thereservoir spring 5 b, while the delivery water line branches off fromthe casing at the level of the lower end of the closing spring 3 b.

The closing spring 3 b and the pressure reservoir spring 5 b are tensionsprings in the case of this embodiment of the suction ram of FIG. 2.

The ram pump shown in FIGS. 1 and 2 operates as follows:

The propulsion water flows through the propulsion water line 1 andstresses the pressure reservoir spring 5 b via the propulsion waterpressure acting on the piston 5 a (pressure reservoir phase), until thepressure on the area of the ram pump valve piston 3 a, less the area ofthe valve seat 6, overcomes the force of the restoring or ram pump valveclosing spring 3 b. The ram pump valve 3 then opens abruptly, since asthe opening begins the propulsion water pressure acts on the area of theentire ram pump valve piston 3 a. The reservoir spring 5 b is nowrelieved (relief phase), in that it accelerates the mass of water in thedelivery line 2 via a reciprocating movement of the piston 5 a, as aresult of which the pressure in this line falls until the force of theclosing spring 3 b overcomes the pressure on the entire area of the rampump valve piston 3 a and the ram pump valve closes. In the renewedpressure reservoir phase which now follows, the water flowing further inthe delivery line 2 sucks water out of the bottom valve 4 until thewater flow comes to a standstill because of the counter pressure as aresult of the delivery head. Further relief and pressure reservoirphases then proceed cyclically.

The ram pump shown in FIG. 2 runs cyclically through pressure reservoirand relief phases, like the ram pump shown in FIG. 1. In contrast to theram pump shown in FIG. 1, in the case of the ram pump of FIG. 2 thepressure reservoir piston 5 a, because of its spring coupling to the rampump valve piston 3 a, partially takes over the changeover function ofthe latter. This means that the propulsion water stresses the pressurereservoir spring 5 b via the propulsion water pressure acting on thepiston 5 a (pressure reservoir phase) until the pressure on its area,less the area of the valve seat 6, overcomes the force of the restoringor ram pump valve closing spring 3 b. The ram pump valve 3 then opensabruptly, since as the opening begins the propulsion water pressure actson the area of the entire pressure reservoir piston 5 a. The pressurereservoir spring 5 b is now relieved (relief phase), in that itaccelerates the mass of water in the delivery line 2 via a reciprocatingmovement of the piston 5 a, as a result of which the pressure in thisline falls until the force of the closing spring 3 b overcomes thepressure on the entire area of the pressure reservoir piston 3 a and theram pump valve closes. In the renewed pressure reservoir phase which nowfollows, the water flowing further in the delivery line 2 sucks waterout of the bottom valve 4 until the water flow comes to a standstillbecause of the counter pressure as a result of the delivery head.Further relief and pressure reservoir phases then proceed cyclically.

In FIG. 2, there is additionally arranged in a free space of the casing10 above the piston 3 b an air-filled hose 8, which buffers thepulsating movements of the ram pump valve piston 3 b and of the water inthe delivery line 2, by which means a relatively quiet mass flow isensured at the ram pump outlet 9. Other known means for buffering can inprinciple also be used.

The object of the present invention is to provide a hydraulic ram pumpwhich, given a compact construction, ensures a high efficiency and along lifetime, and can be operated both to increase pressure and toincrease volume flow.

Accordingly, the hydraulic ram pump according to the invention is inprinciple constructed as shown in FIGS. 1 and 2 and explained above. Aspecial feature of the ram pump according to the invention consists in amechanical coupling of the valve seat of the ram pump valve to the valveseat of the bottom valve in such a way that the kinetic energy whicharises when closing one valve is transmitted to the other valve for thepurpose of opening its valve member. In addition to the advantagesalready treated above of a ram pump of this type, this achieves morefavorable operation in terms of energy. A further advantage is that thedetrimental section between the two valves, which represents a problemin the prior art, since the kinetic energy of the water in thisconnecting section cannot be utilized and, when the ram pump closes, canlead to cavitation in the latter, can be kept optimally short. Finally,a compact construction of the ram pump is ensured by the fact that theram pump valve and the bottom valve are arranged directly adjacent toeach other and axially.

The compact construction benefits from a design of the pressurereservoir in the shape of a bellows which carries the valve member ofthe ram pump valve at one end. Likewise beneficial to the compactconstruction is the arrangement of the restoring spring for the valvemember of the ram pump valve inside the pressure reservoir bellows.Finally, according to the invention the compact construction benefitsfrom the formation of the restoring spring for the bottom valve in theshape of a bellows which is arranged in the pump in such a way that thedelivery water passes through it.

The invention is explained in more detail below by way of example usingFIG. 3. of the drawing; this shows a longitudinal sectional view througha preferred embodiment of the ram pump according to the invention. Partswhich are functionally identical to those in FIGS. 1 and 2 aredesignated in FIG. 3 by the same reference numbers.

The ram pump shown in FIG. 3 has a generally tubular casing 20 having acylindrical jacket 21 which is closed at one end, the lower end in FIG.3, by a bottom 22 and which is closed at its other end, the upper end inFIG. 3, by a lid 23. The interior of the tubular casing 20 is subdividedaxially by a partition 24 into a larger-volume subchamber 25 and asmaller-volume subchamber 26.

The bottom 22 of the casing 20 is designed in two parts in theembodiment shown and comprises a ring 27 whose outer circumferencecorresponds to the outer circumference of the jacket 21, and whoseacentric inner circumference has an internal thread into which a closurestopper 28 with an external thread is screwed. In order to seal off theparts 27 and 28 in relation to each other, there is designed at theouter circumference of the closure stopper 28 an annular groove in whichthere is seated an O ring 29 which is supported on the innercircumference of the ring 27.

A propulsion water line, not shown, is connected to an inlet pipe 30which passes through a hole in the lid 23 and a corresponding hole inthe partition 24. The inlet pipe 30 is tightly connected at least to thepartition 24. Inserted tightly into a further hole in the partition 24is a tubular valve seat carrier 31 which has an annular part 4 aprojecting into the smaller subchamber 26, said annular part 4 a formingwith its outside pointing toward the lid 23 a valve seat 4 b of thebottom valve 4, which in addition has a restoring spring 4 c which isformed as a bellows, to one end of which the valve member 4 b is firmlyconnected and the other end of which is firmly connected to a pipeconnection 32 which passes through a hole in the lid 23, is firmlyconnected to the latter and is connected to a delivery line, not shown.Formed at the other end of the valve seat carrier 31 is a valve seat 6in the shape of a conical surface which tapers in the direction of thevalve seat 4 a of the bottom valve 4 and, for the purpose ofcooperation, cooperates with a spherical surface, complementary thereto,formed on the valve member 3 a of the ram pump valve 3, which islikewise formed in the shape of a circular disk which is firmlyconnected to one end, the upper end in FIG. 3, of a bellows 5 which, asexplained below, forms the pressure reservoir of the ram pump and isfirmly connected with the other end to the inner surface of the closurestopper 28 in the bottom of the casing 20. Supported on the inside ofthe annular ram pump valve member 3 is a restoring spring 3 b, whoseother end is supported at the upper end of a supporting pipe 33 which isinserted with its other end in a hole in the closure stopper 28 and isfirmly connected to the lather. At the lower end, the supporting pipe 33is penetrated radially by holes 34 which, on the one hand, open into theinterior of the pipe 33 and, on the other hand, open into the innerspace enclosed by the bellows 5.

The valve body 3 a of the ram pump valve 3 has a central hole which ispenetrated by a cylindrical body 35 which, with its end pointing towardthe bottom valve 4, projects into the inner space enclosed by the valveseat carrier 31 and is broadened at the other end in the manner of aflange, this flange-like end part serving for fastening the valve body 3to the bellows 5. On that side of the flange pointing toward the bellows5 there is formed a retaining body for the restoring spring 3 b, thisspring engaging around said retaining body. This body, as well as theflange end of the cylindrical body 35 and the latter itself, arecompletely penetrated by a capillary bore which finds its extension in acapillary tube 36 which extends as far as into the bottom region of theretaining pipe 33.

The jacket of the casing 20 is preferably pierced at a plurality oflocations in the region of the smaller subchamber 26, and metal screens37 and 38 are seated in these piercings.

As is shown schematically in FIG. 3 by a wavy line at the upper end ofthe ram pump, the latter is immersed below the surface of a waterreservoir.

The mode of operation of the ram pump according to the invention, whichis constructed as explained above using FIG. 3, is explained below.

Propulsion water is pumped by an external pump (not shown), via theconnecting nozzle 30, into the lower sub-chamber or pressure chamber 1of the ram pump. Since the valve member 3 is held by the restoringspring 3 b in the closed position against the valve seat 6 of the rampump valve 3, the pressure in the pressure chamber outside the bellows 5rises, and this rising pressure leads to an elastic deformation of thebellows 5, which preferably consists of metal. This means that the foldsof the bellows 5 fulfill the function of a spring reservoir for thehydraulic suction ram.

The liquid pressure building up in the subchamber 25 effects anincreasing force on the end face of the bellows 5 carrying the ram pumpvalve member 3 a, and this pressure finally overcomes the closing forceof the restoring spring 3 b. As a result, the ram pump valve 3 opens, orits valve member 3 a comes free of its valve seat, and the liquidpressure which is present in the pressure chamber 25 now acts on theentire end face of the bellows 5 and, respectively, the outer face ofthe valve member 3 a, as a result of which the ram pump valve 3 opensstill further, and as a result of which the pressure in the subspace 25falls slightly. In addition, with the ram pump valve 3 open, thepressure in the subchamber 25 acts on the inner space of the bellows 4c, which forms the restoring spring for the bottom valve 4, which isstill closed at this time, and the delivery water which is present inthis inner space, and accelerates the latter, as a result of which thepressure falls further until it falls below that value at which therestoring spring 3 b presses the valve body 3 once more against itsvalve seat and thereby closes the ram pump valve, the pressure in thesubchamber 25 being built up once more.

The kinetic energy which is transmitted to the associated valve seat 6by the closure of the rampump valve 3 is transmitted via the valve seatcarrier 31 to the valve seat 4 a of the bottom valve 4, and opens thisvalve as a result of this elastic shock. At the same time, the kineticenergy entrained in the delivery water is used up, in that the deliverywater sucks water from the surroundings against the weight of thedelivery water through the bottom valve 4, which is now open, the valvebody 4 b being lifted off the valve seat 4 a. At the same time, thebottom valve 4 is held open by a slight negative pressure in the bellows4 c. As soon as the energy contained in the delivery water has been usedup, the bottom valve 4 is closed once more by the spring force residentin the bellows 4 c.

The kinetic energy of this closing process is transmitted by an elasticshock via the valve seat carrier 31 to the valve seat 6 of the ram pumpvalve 3 and by the latter to the valve member 3 a of the ram pump valve3, as a result of which the latter is opened. At the same time, thedelivery water which has just remained stationary swings back slightlybecause of the elasticity of the bellows 4 c and produces a smallsetting shock which promotes the opening of the ram pump valve.

Because of the valve seats, which according to the invention aremechanically coupled or formed in one piece, for the bottom valve 4 andthe ram pump valve 3, the closing energy of the respective valve isadvantageously employed to open the respective other valve. Thisadvantage cannot be achieved in the case of ram pumps of conventionalconstruction, since the valve seats of the two valves under discussion(the bottom valve is a nonreturn valve) are designed to be separate fromone another, so that kinetic energy cannot be transmitted from one valveto the other. The kinetic energy which is released during the closure israther dissipated by means of damping, for example in the sealing rubberof the valve. Damping of this type is conventionally also necessary inorder to prevent the so-called bouncing of the respective valve memberon the valve seat. In the case of valves which are designed according tothe invention, connected to each other via the valve seat or formed as amaterial unit, this bouncing does not occur, since the kinetic energy isintroduced by the closing valve into the other valve, in order totrigger or to promote its opening.

Conventionally, the flow round a valve member is axial, and the flowruns apart radially between the valve member and the valve seatfollowing the inflow. By contrast with this, the flow in the valveswhich are designed according to the invention with a common valve seatruns radially inwardly together between the valve members and theassociated seats and then axially away from the respective valve. It isonly this that provides the capability of a common valve seat. A furtheradvantage of the coupling of the valve seats of the two valves,according to the invention, consists in the fact that the sectionbetween the two valves can be kept negligibly short.

By means of a simple measure, the ram pump according to the inventionand explained above can also be operated as a normal ram. For thispurpose it is merely necessary to provide an additional spring which hasthe effect that the bottom valve 4 is open in the rest position. Themode of operation of this modified ram pump is as follows:

Initially, the delivery water is accelerated because of its naturalfall, and it emerges into the open through the opened bottom valve 4 viathe tube connection 32 until a hydrodynamic negative pressure betweenthe valve member 4 b and the valve seat 4 a and a backpressure in thebellows 4 c effect the closure of the bottom valve 4. As a result, theram pump valve 3 opens, and the kinetic energy of the delivery watercharges the spring reservoir (bellows 5), as a result of which the rampump valve 3 closes once more and the process, as explained above,begins again from the beginning. However, if the spring reservoir(bellows 5) is already charged (that is to say no water under pressureis consumed), the bottom valve 4 does not close when the delivery waterhas come to a standstill but only after the excess energy from thespring reservoir has accelerated the delivery water in the conversemanner or backward. Following the closure of the ram pump valve 3, thedelivery water then initially sucks water in through the bottom valve 4,until the flow direction reverses. This means that, if no water underpressure is needed, the consumption of delivery water also returns to aminimum.

The purpose of the capillary tube 36 or the capillary opening in thevalve member (FIG. 3) is that the pressure in the interior of thebellows 5 becomes equal to the average pressure in the bellows 4 c andin the delivery line. This achieves the situation where the pressuredifference between propulsion water and delivery water, at which the rampump valve opens, is independent of the delivery head. And as a resultthe load on the external propulsion water pump is always the same,irrespective of whether the ram pump is employed to deliver largequantities of surface water or small quantities of water from a greatdepth.

What is claimed is:
 1. A hydraulic ram pump, comprising: a propulsionwater line (1), a delivery line (2) which receives delivery water via abottom valve (4), a ram pump valve (3) which is connected to thepropulsion water line (1) and delivery line (2), the propulsion waterflowing into the delivery line when the ram pump valve (3) is open and,after closing of the ram pump valve, the water column flowing further inthe delivery line sucking in delivery water via the bottom valve (4),the ram pump valve (3) being arranged coaxially with the bottom valve(4) with mutually adjacent valve seats and held by spring force in itsclosed position separating the propulsion water line from the deliveryline, and a pressure reservoir (5) being provided, which is connected tothe propulsion water line upstream of the ram pump valve (3) in thedirection of flow wherein the pressure reservoir (5) has a bellows whichis supported at one end in a subchamber (25) of a two-part casing and isacted on externally by the propulsion water, which is conducted intothis subchamber (25) of a two-part casing and is acted on externally bythe propulsion water, which is conduced into this subchamber (25) viathe propulsion water line (30), and which carries at the other end thevalve member (3 a) of the ram pump valve (3), the valve seat (6) ofwhich is seated in a partition (24) subdividing the casing (20) and isconnected to the valve seat (4 a) of the bottom valve (4), and which isarranged in the other subchamber, which communicates with the deliverywater.
 2. The hydraulic ram pump as claimed in claim 1, wherein the rampump valve (3) and the bottom valve (4) are essentially arrangedcoaxially, with mutually adjacent valve seats.
 3. The hydraulic ram pumpas claimed in claim 1, wherein the two valve seats (4 a, 6) are formedat the opposite ends of a valve seat carrier (24).
 4. The hydraulic ramovum as claimed in claim 1, wherein the bellows (5) serves as anelastic, variable-volume component of the pressure reservoir, withoutchanging its axial extent in order to store pressure.
 5. The hydraulicram pump as claimed in claim 1, wherein a restoring spring (3 b) for theram pump valve (3) is arranged in the interior of the pressure reservoirbellows (5), runs coaxially with the latter and is supported with oneend on the inside of the valve (6) of the ram pump valve (3) and withits other end on the casing (2).
 6. The hydraulic ram pump as claimed inclaim 1, wherein the valve member (3 a) of the ram pump valve (3) ispenetrated by a capillary bore which connects the interior of thepressure reservoir bellows (5) to the space between the valve member (4a) of the bottom valve (4) and the valve member (6) of the ram pump (3).7. The hydraulic ram pump as claimed in claim 5, wherein a capillarytube (36), which extends as far as into the bottom region of thepressure reservoir bellows (5), is connected to the capillary bore. 8.The hydraulic ram pump as claimed in claim 1, wherein the bottom valve(4) has a bellows (4 c) which at its one end carries the valve member (4a) of the bottom valve (4), and at its other end is supported on thecasing (20) in such a way that this valve member (4 b) is forced againstits valve seat (4 a) in the closed position.